im trying to replace the heater core in a 1986 cj 7. i cant figure out how the housing is attached. a friend told me that i have to remove some nuts on the engine side of the firewall. ive done that an it is still fastened. i only found 3 nuts to remove. its possible that i missed some but i cant find them anywhere. does anybody know how to get this thing out?

Yep it is bolted/screwed from both sides and sometimes pookied tightly to the firewall. Just look real good and if you can't see all the waay around FEEL for boltheads.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

what do you mean "bolted from both sides"? are there bolts i have to remove from the dash side of the firewall?

87 to 95 Wrangler
If you have a/c remove the screws that hold the a/ac unit up and move it to the floor. Then remove the glove box to get a better view of under the dash. disconnect the 2 cables 1 for the temp door the other for the defrost/heat door. disconnect the defrost air duct hose. Now for the engine compartment side. Remove the battery and tray. disconnect the wire and the little hose under the blower motor. disconnect the heater hoses. there are 3 to 4 - size 7/16 nuts 1 under the battery tray another to the right of that, another to the right of that one. the last nut is on the firewall on the drivers side by the back of the valve cover. now you're ready to push the unit back into the passenger compartment. be sure to put rags to absorb the anti-freeze that will pour out of the old heater core. Now that you have the unit on the floor. Theres a vent/cover to the right that has a cable attached. remove the 5-8 screws and the cover should come off and moved to the side without detaching the cable. Now just maneuver the black heater case out and exchange the heater core. be sure to set the 2 moving doors in their place when you put the cover back for the heater core...
Ok!
Big JIm
<img src="/forums/images/graemlins/pfft.gif" alt="" />

On 1986 CJ7's, there are four bolts on the heater assembly that hold the heater assembly to the firewall. These bolts are captive bolts on the heater assembly, and they protrude forward through holes in the firewall. There are rubber grommet-like seals on the bolts that sometimes get sticky and want to adhere to the inside of the firewall. There are nuts on the engine side of the firewall that screw onto these four bolts. Three of the bolts are in the area of the battery tray -- two fairly high and one fairly low. The fourth bolt is more toward the center of the firewall.

In addition to removing those four nuts, you'll have to take off the two heater hoses, the heater motor power connection under the battery tray, and the small heater assembly drain hose under the battery tray. You'll have to remove the three control cables coming from the dash, as well as the plug on the resistor connection on the right side where the heater assembly joins the input vent assembly. Before reinstalling it, you should get two new seals -- the one that the two pipes for the heater hoses go through, and the one that fits arouond the heater motor and the power connection.

Depending on how tight the fit it, you may also have to remove the input vent assembly -- that's the thing that gets air through the vents in the top of the cowl, and it plugs into the top right section of the heater assembly. The only thing holding the input vent assembly in is the four flat-head screws under the vent cover plate. You will probably also have to remove the big drain hose from the input vent assembly.

Any problems, get back to me. I just removed and installed all that stuff when I replaced the metal body tub with a fiberglass tub this year.

thanks for the info. ive been in the field and im just now getting back to the shop. ill look for the 4th nut and try to put a little muscle to it. thanks again.

Bob is correct. There are four nuts, you missed one somewhere. From what I remember, the farthest one over from the passenger side is right behind the valve cover (if you got a I-6). There are two near the center and one under the battery tray...or somewhere thereabouts. The one by the battery tray MIGHT be between the battery and fender now that I think about it.
Mike